Morphological studies of honey bees in the northern wooded steppe zone of the Republic of Bashkortostan

The article presents assessment results for the preservation of European dark honey bees in the northern wooded steppe zone of the Republic of Bashkortostan, which is an integral structure in the honey bee Apis mellifera mellifera population of northern Bashkortostan. Bee farms of 24 settlements in Askinskiy, Arkhangelskiy, Baltachevskiy, Karaidelskiy and Yanaulskiy districts show the persistence of taxonomically pure bees, which stands for 73 % of the samples. During the bee-breed identification, the most volatile parameters were determined (the length the rostrum, the length and width of the right hemelytron, the cubital index) that are greatly influenced by the hybridization processes. The presence of registered pure-breed bee colonies speaks of the biopotential of the European dark bee population in the farms of the given region, which will allow to create pedigree breeding units and pure breeding zones for native bees in the future.


Introduction
The breeding work on bee farms of any levels nowadays is mostly connected with increasing the productivity of bee colonies by producing and using hybrid bees. The scientific validity of this method is beyond questioning, as well as the use of the heterosis effect that allows to significantly increase the productivity of colonies if good cross-breed combinations are found. The success of such activities depends on access to biologically pure materials [1][2][3][4].
Konusova O. L. et al pointed out that the main goal of bee-keeping is the increase of productivity of colonies, which is mainly characterized by winter hardiness, melliferous capacity, and the productivity of the queens. To achieve this goal, it is crucial to have a biological and economic assessment of bees, finding the pure breed colonies, and producing highly-fertile queens [5].
The importance of preserving pure-breed bees was noted by V.A. Gubin, who wrote in one of his works (1984): "under the conditions of uncontrolled mating at bee farms surrounded by colonies of different or unknown breeds, which is often the case, the question of practical usage of the heterosis effect is not easy and obvious" [6]. The author also claimed that it must be kept in mind that cross-breed hybrid may often have 'inferior parameters' [6].
At the same time, N.V. Ostroverkhova et al claim that the genetic diversity typical of natural populations is one of the most important conditions for the sustainable development of bee farming [7]. Currently, the global loss of diversity and numbers of bees is evident all over the world, therefore one of the key objectives of beekeeping must be the preservation of native breeds and populations of the honey bee.
Within the Republic of Bashkortostan (RB), according to some researchers, several populations are preserved in Tatyshly, Aksiпо and Baltachevo apart from the Burzyan population, which all put together can comprise the north Bashkir population of Apis mellifera mellifera [8,9]. Taking into consideration that the processes of global hybridization and pure-breed population disappearance take place in all of the regions, the research aimed at preservation monitoring is of the highest scientific and practical significance.

Materials and Methods
The study objects are the imagos of honey beesworkers ( Fig. 1). The field research (2010-2018) was carried out in bee farms in administrative districts of the northern wooded steppe zone of the Republic of Bashkortostan: Askinskiy, Arkhangelskiy, Baltachevskiy, Karaidelskiy, Nurimanovskiy and Yanaulskiy (Fig. 2). The total of bee colonies (farms/settlements) was 1300 per 28 settlements. We used a standard morphometric method for the assessment of worker bees.

Fig. 1. Worker honey bee specimen
The data obtained were compared with the established European standards from the literature [10]. To analyze the consolidated data, we used the Statistica software version 6.1.

Results and Discussion
The results of the morphological study of worker honey bees (Apis mellifera) from the northern wooded steppe zone of Bashkortostan are presented in Table 1.
However, the lower limit values for bees from Novokulevo, Novoisayevo, and Urman comply with the standard of the European dark bee, while the upper limit is beyond its requirements. In Nikolskoye, the limit values of bees are not compliant with the breed standard. The hemelytron length and width values in two of the farms did not comply with the breed standard (in mm): Novokulevo (8.99±0.10) and Novoisayevo (8.98±0.08), and in two others, they did: Nikolskoye (9.00±0.09) and Urman (9.02±0.17). The average hemelytron width were in compliance with the European dark bee standard In Yanaulskiy district, the sampling was carried out in the following settlements: Bayguzino, Isanbayevo, Yambiyevo, Akhtiyal, and Sandugach. The total of colonies is 200. The bees complied with the breed standard in all parameters. The average rostrum lengths (in mm) is as follows: Bayguzino -6.16±0.16; Isanbayevo -6.27±0.08; Yambayevo -6.26±0.07; Akhtiyal -6.25±0.12; Sandugach -6.27±0.07. The hemelytron length averages were within the following ranges (in mm): 9.44±0.24 (Bayguzino), 9 Novoisayevo. It is also worth noting that during the honey bee breed identification, the most volatile parameters were determined (the length the rostrum, the length and width of the right hemelytron, the cubital index) that are, in our opinion, greatly influenced by the hybridization processes. Among the key factors for these biological phenomena are, first of all, a lasting expansion of new breeds and breed groups, as well as the lack of scientifically grounded selection and breeding activities both on particular bee farms and in the wooded steppe zone of Bashkortostan in general. However, the presence of pure-breed bee colonies signifies that the European dark bee population in this region has certain biopotential.

Conclusion
It is well known that local adaptations of honey bees are unique and conservative. However, some actions that do not take into consideration the standpoint of population biology lead to the disappearance of native populations, which is true about the Bashkir honey bee population. The research carried out in the northern part of RB shows that 950 (73 %) of the bee colonies out of 1300 belong to the European dark bee, which proves the presence of the local population in the area which used to belong to the mountain and forest ecotype. We believe that the domination of the European dark bee is due to the reserve in Tatyshlinskiy district and the areas bordering the Perm region, the low amount of agricultural lands, the presence of lime trees, and the closeness of Birskiy and Askinskiy wildlife sanctuaries that perform some environmental activities.
In the future, the creation of breeding farms will allow for the replenishment of pedigree material for amateur and professional bee farms, and it will be the first step in the transition to the pure-breeding. That being said, the next step is the creation of the 'pure' breeding area in the northern part of RB, and a key instrument in this respect is setting up drone barriers with respect to the protected breed.